This invention relates to a system for illuminating stairs when in use. More particularly, the invention relates to an improved apparatus which utilizes electrical potentials of reduced intensity to provide illumination of a plurality of stairs when the stairs are being used, e.g., by one or more human beings.
Darkened stairways can be very dangerous. It clearly would be desirable to illuminate such passageways. However, continuous lighting may be expensive and wasteful since stairways are often used only intermittently. Thus ideally, stairways should be lighted only when in use.
A prior art search made relative to the present invention identified the following U.S. Pat. Nos.: 934,122; 2,756,323; 2,911,519; 3,596,024; 3,017,497; 3,753,217; and 4,164,637.
One object of this invention is to provide an apparatus useful to illuminate stairs while the stairs are in use.
Another object of the present invention is to provide an apparatus useful to illuminate stairs which utilizes reduced electrical potentials. Other objects and advantages of the present invention will become apparent hereinafter.
An improved apparatus adapted to illuminate a plurality of stairs as one or more persons utilize the stairs has now been discovered. The system, ultimately powered by an A.C. (alternating current) line voltage source (such as is conventionally used in the United States), includes a transformer means adapted to reduce the A.C. line voltage from the source to provide a reduced A.C. voltage. At least one light means, preferably a plurality of light means connected in parallel to each other, is (are) located in proximity to the stairs. Such light means acts to illuminate the stairs when at least a portion of the reduced A.C. voltage is supplied to the light means and an electrical circuit including the light means is formed. Also included is a rectifier means associated with the transformer means and acting to convert the reduced A.C. voltage to a D.C. (direct current) voltage. A plurality of pressure sensitive switch means, e.g., conventional pressure sensitive grids or mats, are associated with the rectifier means so that at least a portion of the D.C. voltage is supplied to the pressure sensitive switch means. Each of these switch means is located in association with the tread of at least one of the stairs so that such switch means is closable in response to pressure, e.g., foot pressure, from a person using the stairs being applied to or placed on such tread. A relay means is provided in association with the pressure sensitive switch means and the light means. This relay means is adapted to form the electrical circuit including the light means in response to at least one of the pressure sensitive switch means being closed.
The present system functions to illuminate a plurality of stairs in response to the indicated presence of a person using the stairs. Thus, this apparatus provides light when it is needed, e.g., to guide a user of the stairs. Valuable energy is conserved because, for example, the light means may not illuminate if no one is using the stairs. Also, the reduced voltages or electrical potentials employed provide an added safety feature. In short, the present apparatus provides an effective reliable, inexpensive and safe system for illuminating a plurality of stairs.
In one preferred embodiment, the present device further comprises manual switch means associated with the light means. This manual switch is capable of being manually closed so as to cause the light means to illuminate the stairs irrespective of whether any of the pressure sensitive switch means are closed. This manual switch feature allows one to illuminate the stairs while not in use, e.g., for display or other purposes.
The light means, preferably a plurality of light means may be any switch device or devices capable of illuminating the stairs and also capable of operating with reduced A.C. voltages. It is preferred that each light means, e.g., incandescent light bulb, be located in association with the riser of a different one of the stairs to be illuminated.
The rectifier means also may be any device suitable to perform its function as set forth above. In one preferred configuration the rectifier means includes a diode and a capacitor in series.
It is preferred that each of the pressure sensitive switch means be associated with the tread of a different one of the stairs to be illuminated. Thus, in this embodiment, foot pressure on any of the stairs will cause the light means to illuminate the stairs.
Although any suitable relay means may be used, a preferred embodiment includes relay contacts, a relay coil and a relay capacitor connected in parallel with the coil. One feature of this preferred configuration is that the light means will give off steady and constant illumination (rather than the light means "flickering") as the stair user moves from the stair to stair, thus creating uneven pressure on the pressure sensitive switch means. In other words, this configuration advantageously provides for steady illumination of the stairs even though the pressure on the pressure sensitive switch means is uneven.
As indicated above, the transformer means acts to provide a reduced A.C. voltage. For improved safety and operation, it is preferred that this reduced A.C. voltage be in the range of about 3 volts A.C. to about 30 volts A.C., more preferably about 6 volts A.C. to about 18 volts A.C. Excellent results are obtained when the reduced A.C. voltage is about 12 volts A.C.
These and other aspects and advantages of the present invention are set forth in the following detailed description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.